41 



SOME PRACTICAL EXPERIMENTS WITH VARIOUS INSECTICIDES 

 FOR THE SAN JOSE SCALE IN GEORGIA. " 



By W. M. Scott, Atlanta, Ga. 



The Georgia State department of entomology was established in 

 March, 1898, and at that time, as shown b}^ inspections made later, 

 the San Jose scale had become established in 57 counties, including the 

 leading orchard sections of the State. No system of treatment had 

 been adopted, most of the owners of infested orchards not having 

 even determined the cause of the trouble. 



In a few instances, however, some knowledge of this pest and its 

 treatment had been g-ained through correspondence with the Division 

 of Entomolog}^ and the Georgia Experiment Station. In the Tifton 

 section some 50,000 peach trees had been subjected to the gas treat- 

 ment, and whale-oil soap was being used quite extensively in Randolph 

 Count}^, but as a rule practically nothing was being done to control 

 this pest. The gas treatment, although giving good results, proved 

 to be too cumbersome, and the soap washes, owing perhaps to lack of 

 thorough application, were unsatisfactory. 



Our State law was such as to compel the treatment of infested 

 orchards, and it was incumbent upon the newly appointed entomolo- 

 gist to furnish the remedy. After some preliminary experiments the 

 oil- water treatment was adopted and a 25 per cent strength of kero- 

 sene was recoumiended for the winter of 1898-99. The results were 

 generall}^ satisfactory, but it was found advisable to reduce the 

 strength to 20 per cent. Experiments with crude petroleum, made 

 the following year, gave this substance the preference, better results 

 being obtained with it than with corresponding strengths of kerosene. 

 For several years, therefore, kerosene and crude oil in mechanical 

 mixture with water have been very extensively used against the San 

 Jose scale in Georgia, and, though on the whole successful, there have 

 been several cases of more or less serious damage to the treated trees. 

 In most cases the damage has been accurately traced to some defect 

 in the pump, carelessness in the application, or other causes within the 

 power of the orchardist to control. But there have been a few cases 

 where the resulting damage could ])e attributed to no fault of the 

 operator. These adverse results gave rise to some distrust of the oil 

 sprays, which was augmented by the arguments of certain vendors of 

 sure-cure washes? and compounds guaranteed to exterminate the scale 

 without damage to the trees. 



In order to test these " cure-all " compounds and other better known 

 scale washes in comparison with the oils officially recommended by 



«For valuable assistance in the execution of these experiments the writer is 

 indebted to Mr. W. F. Fiske, who personally conducted tlie larger portion of the 

 work with the soaps and caustic washes; and to the owners of the orchards, who 

 furnished the teams and labor. 



